Ram-type wood reducing apparatus



Sept. 6, 1960 H. E. ERICKSON ETAL 2,951,519

RAM-TYPE WQ OD REDUCING APPARATUS 5 Sheets-Sheet 1 Filed Aug. 18, 1958 Harold E. E riC'kson Cyrville cLRobinson p 1960 H. E. ERICKSON ETAL 2,951,519

RAM-TYPE WQQD REDUCING APPARATUS Filed Aug. 18, 1958 5 Sheets-Sheet 2 b Hat-01d E. Erickson ur-ville J. Robinson -HVVENTOR$ 2:25-

Sept. 6, 1960 H E. ERICKSON ETAL 2,951,519

RAM-TYPE woon REDUCING APPARATUS 5 Sheets-Sheet 3 Filed Aug. 18, 1958 Harold E. Erickson Cur-ville cLRobinson INVENTORS Sept. 6, 1960 H. E. ERICKSON ETAL RAM-TYPE WOOD REDUCING APPARATUS Filed Aug. 18, 1958 5 Sheets-Sheet 4 J Ha rold EEr-ic kson Curville clRobinson INVENTORS m BY w? Sept. 1960 H. E. ERICKSQN ETAL 5 RAM-TYPE WOOD REDUCING APPARATUS Filed Aug. 18, 1958 5 Sheets-Sheet 5 1N VEN TORS United States Patent RAM-TYPE WOOD REDUCING APPARATUS Harold E. Erickson, Auburn, Wash., and Curville J. Robinson, New York, N.Y.; said Erickson assignor to Dale L. Schubert, Tacoma, Wash., and said Robinson assignor to Industrial Development 00., Inc., Seattle, Wash., a corporation of Washington Filed Aug. 18, 1958, Ser. No. 755,533

7 Claims. (Cl. 144-17 2) This invention relates to ram-type apparatus for re ducing wood to small pieces. It pertains particularly to ram-type apparatus for reducing wood to flakes for use in the manufacture of wood composition boards.

Various types of wood reducing apparatus have been devised heretofore for flaking wood blocks or logs by feeding them against a rotary cutter head. However, such apparatus has been diflicult to feed, particularly if the feed blocks or logs are of random dimensions; has failed to produce a comrninuted wood product of sufficiently uniform dimensions to produce a composition board of uniform properties; or has had a relatively low production rate. It is the general object of the present invention to provide wood reducing apparatus which overcomes these disadvantages.

The manner in which the foregoing and other objects of this invention are accomplished will be apparent from the accompanying specification and claims considered together with the drawings wherein like numerals of reference indicate like parts and wherein:

Fig. 1 is a View in rear elevation of the herein described wood reducing apparatus in one of the its embodiments;

Fig. 2 is a View in side elevation of the apparatus of Fig. 1;

Fig. 3 is a plan view of the apparatus of Figs. 1 and -2 looking in the direction of the arrows of line 3-3 of Fig. 2;

Fig. 4 is a sectional view taken along line 4-4 of Fig. 1;

Fig. 5 is a sectional view similar to Fig. 4, but illustrating the herein described wood reducing apparatus in a second embodiment;

Fig. 6 is a schematic diagram of an hydraulic circuit employed in the apparatus of Figs. 1-4;

Fig. 7 is a schematic diagram of an hydraulic circuit employed in the apparatus of Fig. 5; and

8 is a view in side elevation of the apparatus of The apparatus of Figs. 1-4 and 6 1 A frame indicated generally at 10 supports a motor 12 coupled to a rotary cutting head 14. The latter may be variously constructed as required to cut flakes or chips from wood logs or blocks 16. It operates in conjunction with an. anvil 18 and the flakes produced are discharged through a guide shoe 20.

The logs are fed cross-gain to the cutter head by a ram assembly driven by an hydraulic cylinder 22. This cylinder is trunnion mounted between parallel frame members and its piston rod'is pivotally connected to tabs 24 which are welded to a cross-bar 26 the axis of which is substantially parallel to the axis of cutter head 14. Bar 26 is supported by a pair of arms 28 keyed to a horizontal, pivotally mounted shaft 30. A pair of pusher arms 32 are keyed to the same shaft, one at each end thereof. Limit switches 34, 36 are positioned for contact by one of the arms.'

Crossbar 26 supports a plurality of spaced, parallel, serrated plates 40, the teeth of which are arranged on an arc concentric with the periphery of cutter head 14. Their function is to engage a log 16 and force it at a uniform feed rate against the cutter head for reduction into flakes.

Means are provided for holding the log securely as it is reduced by the cutter head. To this end, there is provided a grid composed of spaced, parallel plates 42 mounted on a crossbar 44 supported between arms 46. The latter arms are mounted on shaft 30', on which they turn freely. The piston rod of a fluid operated cylinder 56 is pivotally connected to tabs 52 on cross bar 44. Plates 42 thus form a floor upon which the log is supported and across which it slides as it is fed to the cutter head. However, it may be withdrawn by operation of cylinder 50 as required for cleaning or servicing.

The log is further positioned by means of a plurality of vertical, parallel, hold-down arms 54. The upper end of each arm is connected by means of pins 56 to a substantially horizontal supporting arm 58. Each of the latter is pivotally mounted on a shaft 60 by means of bearings 62. The lower portions of each of hold down arms 54 is pivotally connected by pin 64 to a substantially horizontal supporting arm 66 pivotally mounted by bearings 68 on a supporting shaft 70.

Supporting arms 58, 66 remain substantially parallel to each other at all times. Accordingly, pantograph action maintains the working ends of hold-down arms 54 closely adjacent the periphery of cutter head 14, but without even coming in contact with it. Hold-down arms 54 are maintained resiliently in pressure contact with the log by means of air cylinder 72, one for each arm. The piston rod of each. cylinder carries a cross head 74 which is pivotally connected to the corresponding arm by means of pin 64.

Air under constant pressure is supplied to the cylinders, which accordingly act resiliently, continuously urging the arms downwardly into contact with the log, but being at the same time retractable against the fluid pressure as required to accommodate irregularities on the log, or logs of increased diameter.

Thus the log. being operated upon by the cutter head is maintained securely in place by the serrated edges of plates 40, the grid floor formed by plates 42, and the lower surfaces of vertical hold-down arms 54. As a consequence, it can be advanced at a uniform feed rate against the cutter head and flakes of uniform dimensions are produced with minimum formation of splinters and sticks.

After each log has been reduced, cylinder 22 retracts. This withdraws the ram assembly from the cutter head so that a new log can be introduced. it is a particular feature of the present invention that means are provided for measuring each log and regulating the extent of retraction of the ram assembly accordingly. This prevents over-running on the retracting stroke when the logs are of random diameter, as is usually the case. Means also are provided for retracting the plates at a rapid rate, as compared with the rate of their advancement. These two factors materially increase the production rate of the apparatus.

In the embodiment of Figs. l-4 and 6, the log measuring and feed rate control apparatus includes a pair of arms mounted and freely rotatable on shaft 30. Each of these arms carries a projection 82 positioned for contact by pushing arms 32 by means of which they are retracted. Resilient means such as air cylinders 86 supplied with air at constant pressure are connected to arms 80for urging them continuously forwardly in the direction. of the cutter head.

are rigidly afiixed a plurality of spaced, parallel, logguide members 90. These are so arranged as to direct a log placed thereon downwardly onto the upper edges of serrated plates 40 when the latter are in advanced position.

Standards 92 extend upwardly and outwardlyfrom cross bar 88. They support a rotatably mounted bar 94 to which are aflixed a plurality of parallel, spaced fingers 96. The upper surfaces of the fingers extend above the upper surfaces, of guide members 90 so that when a log is placed on the assembly, it contacts the fingers first, depressing them, and rotating bar 94 in a clockwise direction (Figs. 2 and 4). An arm 98 rigid to the bar thereupon is moved into engagement with an electric switch.- 100.

Upon passage of the log over the guide members, the depressed fingers are returned to their extended position by means of lever arm 102 rigid to bar 94 and connected by spring 104 to bar 88.

The logs may be fed to the herein described apparatus by means illustrated in Fig. 2. Each log is located by a conveyor 110 sliding in a trough 112. When the log is positioned properly, it may be pushed off the conveyor and onto guide plates 90 by pushing arms 114 mounted on a rock shaft 116 and actuated by a suitable motor such as fluid operated cylinder 118. A switch 120 is positioned for contact by arms 114 during their operation, and this switch is in the circuit of an electric control for the conveyor 110 to prevent operation of the latter until the arms 114 are in position to receive a log.

An hydraulic circuit for use in conjunction with the apparatus of Figs. l-4 is illustrated in full lines in Fig. 6. A motor driven pump 124 pumps hydraulic fluid from a reservoir 126 through line 128 to a solenoid operated four-way valve 130. The advancing stroke of drive cylinder 22 is effected when this valve directs the flow of fluid through line 132 to the back of the cylinder. As the piston rod' extends, fluid passes through line 134, line 136, and fiow control valve 138, which regulates the speed of advancement of the cylinder. It then returns through valve 130 and line 140 to reservoir 126. During this operation by-pass line 142 is closed by check valve 144.

On the return stroke, valve 130 is set to direct fluid outwardly through valve 138 and. line 134 to the forward end of cylinder 22. However, the fluid also is free to pass through line 142 since check valve 144 is set to pass it. Hence the cylinder advances at a relatively slow, measured rate as determined by the setting of valve 138. However, it returns very rapidly, thereby materially reducing the time required for a complete operating cycle.

Operation of the appanatus of Figs. 1-4 and 6 Logs of random diameters, for example, from 3 to 12 inches, are passed into the apparatus on conveyor 110. When the first log segment is in position, it energizes a limit switch in the circuit of an electric control which operates cylinder 118. Limit switch 34 also is in this electric circuit, and upon closing of these switches the cylinder is operated, kicking the log onto guide plates 90 and thereby depressing pivotally mounted fingers 96. With arm 32 engaging switch 36, an electric circuit is completed for energizing the solenoid 36' for adjusting four-way valve 130 to a position at which pump 124 directs fluid into the forward end of cylinder 22, retracting it at a rapid rate as determined by the capacity of check valve 144 and throttle valve 138.

As the cylinder retracts, it carries with it the ram mechanism including arms 28 keyed to shaft 30, cross bar- 26 between the. arms, and serrated plates 40 mounted on the cross bar. It also carries back with it pusher .arms 32. which strike projections 82 on independently forward edges of plates 40 clear plates 90. Arms 80, together with the feed gauging mechanism including guide plates 90 and fingers 96 which they support, then are pushed back against the resilient force exerted by constant pressure cylinders 86.

When arms 80 and thegauging mechanism have been pushed back sufliciently to permit log 16 to drop downwardly into the feed chamber forwardly of serrated plates ,40, spring pressed fingers 96 snap back to their extended position, operating limit switch 100 which in turn energizes solenoid 100' and reverses the flow of oil to ram drive cylinder 22 through four-way valve 130.

The ram cylinder then extends at a controlled rate determined by the setting of throttle valve 138, driving serrated plates 40 and the log engaged thereby forwardly against rotating cutter head 14.. As it is advanced, it is held securely in position by the serrated plates, and also by hold down arms 54 pressed downwardly by air cylinder 72 in the direction of the grid formed by supporting plates 42.

During the initial portion of advancement of the plates 40 by ram 22, cylinder 86 forces the arms 80 to the forward position shown in Figs. 2 and 4. Upon continued advancement of the plates 40, arm 32 also is advanced until it disengages from switch 34. This switch then closes, activating cylinder 118 to deposit a second log segment on the fingers 96 where it remains awaiting reduction of the first log segment.

When the log has been entirely reduced, arm 32 engages limit switch 36 which again energizes solenoid 36' and reverses four-way valve 130 causing reversal of cylinder 22 and retraction of serrated plates 40. The cycle described above then is repeated, introducing the waiting log into the apparatus and feeding it against cutter head 14.

The apparatus of Figs. 5 and 7 The basic elements of the apparatus of Figs. 5 and 7 are essentially the same as those described above. However, air cylinders 86 are operated differently and a different means of controlling the direction and stroke of ram cylinder 22 is provided.

Thus replacing guide plates and gauging fingers 96 on support bar 88 are a plurality of parallel, spaced, holding plates 150. The hydraulic circuit including ram cylinder 22 then is controlled by means of a cam bar 152, the forward end of which is rigid to a standard'154 on the cross head of the piston rod of the cylinder and the rearward end of which slides freely in guides 156, 158. Cam bar 152 is divided into thick and thin segments, as is clearly evident in Fig. 5. These are in working engagement with a throttle valve 164 which is operated by alternate contact of its cam follower 165 with the thick and thin segments of the cam bar. l

The operation of the apparatus of Figs. 5 and 7 isas follows,-with reference to the complete hydraulic system illustrated in Fig. 7. This circuit includes a by-pass'line 162, the flow through which is controlled by throttle valve 164, the latter being operated by cam follower 165.

Assuming that the apparatus ,is in operation, with ram cylinder 22 extending and serrated plates 40 urging a log against cutter head 14, cylinders 86 are retracted by operation of an electric control valve in the air supply, the valve being actuated by a switch which is contacted by arm 32 at the moment when the leading edges of the serrated plates pass frame member 166 of Fig. 5. As a result, arms 80 are retracted, opening up the space between plates 150 and the abutment wall 168..

A waiting log then may be introduced into this space, for example, by means of conveyor and;rocking arms 114 of Fig. 2. It drops downwardly until it contacts the upper edge surfaces of serrated plates 40.

As the leading edges of the serrated plates approach a predetermined point with, reference to'the cutter'head, f9; example, one about two inches removed therefrom,

insipid arm 32 contacts another switch which actuates the air supply valve, whereupon cylinders 86 are again actuated, but in a forward direction, to advance arms 80 and holding plates 150 until the waiting log is pressed between the latter and abutment Wall 168. It is held there while the preceding log is completely reduced.

When the log is completely reduced, arm 32 engages switch 36 which closes the electric circuit of the solenoid 36 associated wtih the four-way valve 130. Ram cylin der 22 thereupon is retracted rapidly, the oil flowing freely through check valve 144. When the forward edges of serrated plates 40 have passed holding plates 150, arm 32 retracts arms 80 and plates 150, against the air pressure in cylinders 86, permitting the waiting log to drop down in the feed chamber defined by grid plates 42, serrated plates 40, and cutter head 14. Also, time delay switch 35 (Fig. 8) is operated. After a short time delay, characterizing the operation of time delay switch 35, this switch closes the electric circuit of solenoid 35', whereupon four-way valve 130 then reverses the direction of motion of ram cylinder 22 which now advances the serrated plates, and the log, toward the cutter head.

During the first portion of the advancing stroke of the ram cylinder, oil can flow through throttle valve 138 and also through valve 164, which is held open by engagement of the cam follower 165 with the thick forward segment of cam bar 152. This permits the log to be fed toward the cutter head 14 and hold down fingers 54 at a high rate of speed up to a predetermined point. At this point, the cam follower 165 engages the thin segment of cam bar 152 and this movement of the cam follower closes valve 164 so that the feeding rate is controlled entirely by throttle valve 138 and is reduced correspondingly. During the entire cutting operation, the log is held down by vertical arms 54 so that it is maintained resiliently in place and-the formation of flakes of uniform size is encouraged.

Thus it is apparent that by the present invention, there has been provided a ram type wood flaking apparatus of high capacity in which over-running and lost motion of the feed mechanism are eliminated. Furthermore, wood flakes of uniform dimensions are produced with minimum formation of sticks and slivers even though logs of irregular contour and random diameters constitute the feed material.

It is to be understood that the forms of our invention, herewith shown and described, are to be taken as preferred examples of the same, and that various other changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of our invention, or the scope of the subjoined claims.

Having thus described our invention, ,We claim:

1. Wood reducing apparatus comprising a rotary cutterhead, feed means reciprocatable toward and away from the cutterhead for feeding a piece of Wood thereto, drive means connected to the feed means for driving the feed means in advancing and retracting directions, guide means positioned above the feed means for guiding the wood piece to the space between the feed means and the cutter head, guide retracting means operatively connected to the drive means and engageable with the guide means for retracting the same with respect to the cutter head during retraction of the feed means, and contact means positioned on the guide means for engagement by a wood piece, the contact means being operative when disengaged from a wood piece to actuate the drive means to reverse the retracting movement of the feed means and advance the latter when the space between the feedmeans and the cutter head is sufficient to accommodate the wood piece,

2. The wood reducing apparatus of claim 1 wherein the drive means comprises a valve-controlled, fluid-operated cylinder and wherein the contact means comprise pivotally mounted spring-pressed fingers in an electric circuit with the valve control for the cylinder.

3. The apparatus of claim 1 including feed means for feeding logs one at a time to the guide means.

4. Wood reducing apparatus comprising a rotary cutter head, a shaft rotatably mounted parallel to the cutter head axis, feed means including a first pair of arms keyed to the shaft, a first cross bar interconnecting the outer portions of the arms, and a plurality of vertical serrated plates rigid to the crossbar, drive means connected to the feed means for moving the plates toward and away from the cutter head, guide means including a second pair of arms mounted on the shaft and freely pivotal thereon, a second cross bar interconnecting the second pair of arms and positioned above the first crossbar, and a plurality of spaced guide plates rigid to the second crossbar and positioned for directing a log into the space between the serrated plates and the cutter head,

guide retracting means operatively connected to the drive means and engageable with the guide means for moving the guide plates away from the cutter head, and contact means mounted on the second cross bar for engagement by a log contacting the guide plates, the contact means being operative when disengaged from a log to activate the drive means to advance the guide plates and serrated plates when the space between the serrated plates and rotary cutter head is sufficient to accommodate a log.

5. The apparatus of claim 4 wherein the contact means comprise a plurality of pivotally-mounted, spring-pressed fingers interleaved with the guide plates.

6. The apparatus of claim 4 wherein the means engageable with the second pair of arms supporting the guide plates comprises a pusher arm keyed to the shaft and positioned for contact with the second pair of arms after a predetermined retracting rotation of the shaft, and resilient means applying resilient force to the second pair of arms in a direction opposing the force applied by the pusher arm.

7. The apparatus of claim 6 wherein the resilient means comprises a constant pressure air cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 571,019 Roberts Nov. 10, 1896 2,160,920 Strawn June 6, 1939 2,515,923 Hansen July 18, 1950 2,838,080 Spingate June 10, 1958 

